Screw press for dewatering and washing diluted substances



Dec 29, 1931. R. T. LANG SCREW PRESS FOR DEWATERING AND WASHING DILUTED SUBSTANCES Original Filed Feb. 15, 1928 18 Z7 Z0 .5 Z A? 4 5 M k A v 3] H In [HUM 1 I 11, HUI I. i 3

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T Uh \l v INVENTOR ifzaizardflaizg/ M ATTORNEY Patented Dec. 29, 1931 UNITED STATES PATENT OFFICE BICfiARD TJLANG, or HEIDENHEIM-ONV-THE-BVRENZ, GERMANY, AssrGNoR TO AMERI- cAN VOITH CONTACT COMPANY, me, OF NEW YORK, Y., A CORPORATION OF NEW Y RK SCREW rREss FOR DEWAT ING AND WAsiiI q mmrrnn suBsrANc s Original application filed February15, 1928, Serial NO. 254,370. Divided and this application filed February 27, 1929. 'Serial Nd'uaess.

This invention relates to screw presses for dewatering diluted substances; as for instance pulp in paper mills, oil seeds,bagasse, moist grainor the like. .Ithas for its object toimprove the construction and operation of screwv presses so vas to obtain highest consistency and uniform dryness of the whole substance when it leaves the press.

This application is a division of myearlier application, Serial No. 254,370, for patent on :screw presses for dew'atering and Washing diluted substances,filed February 15, 1928.;

With screw presses of the ordinary typeithe substance ,to be pressed 7 out contains more liquor near'the inner circumference of the threads of the screw than near the outer cir- V pulp near the'outer edges of the threads, A

screw'press having this disadvantagecannot be operated safely for pressing out-at high density, because of its tendency toclog up on account Offthe relatively greatfconsist-ency of the substance required near the bottomof the threads. I

It has been proposed to overcome this draw back by providing perforations in the screw press body; inserting stationary or rotating perforated tubes into the; press chamber,

using perforatedoutlet plugs, etc. Such expedients, however, are Objectionable. rFirst a stationary tube as a continuation of the screw proper requires packingmeans within .the press chamber, whichis'neither accessible nor easily controlled, and therefore are liable to give constant troubles, suffer with undue wearand necessitate a: complicated design.

Further, a rOtating tube which can be fastenedto the screw body,- isopelative only, for

relatively low densities and substances giving. v"up the liquor contained therein easily. If slow wood'pulp or the like has tobe pressed 'out,however, to a density of morejthan' the pulp starts to rotate with the tube. vThis rotation acts back upon the pulp within the reach ofthe threads of the screw, so that such pulp will rotate also, thus producing a churningof the pulp instead of discharging it from the press.

complicated and unsatisfactory design comprising the stationary tube and to allow the employment of the rotating tube without incurring its disadvantages I For this purpose I provide obstructing means at the discharge endof the rotating tube to prevent the pulp from turning around with the tube, and at the same time I divide thepulp into separate streams before it leavesjthe outlet of the screw press, I further provide a plugging device at the outlet of the press for the purpose of controlling the density of the discharge pulp;

.andin connectionwith the plugging device n lts immedlate vicinity Iutilize rotating cutting means which disintegrate the'pulp after it has passed the obstructing. means and -breakitiup into small particles, which leave the outlet spout of the press freely. This disintegration of the highly dry pulp at the discharge end is necessary because a coherent mass would accumulate at the supporting means for the plugging device and produce .an uncontrollable back pressure upon the pulp to be discharged, with the result of clogging the machine up in a very short time. Y The drawlngsshow an embodiment of my invention.

Figure ,1 presents a vertical longitudinal sect on through the outlet end of a screw press according to my invention, showing the improvedarrangement of the press chamber with the obstructing and cutting means and the plugging device; and I a Figure2 is atop plan of same.

The same numerals identify the same parts throughout" w V Numeral 1 indicates'ascrewin a perforated shell 2, imbedded in the outer-casingB, to

An object of this invention isto avoid the which the outlet 4 is attached. Fastened to thefframe or body ofthe device adjacent the utlet 4 are two rods 5} which carry a member 6 with the bearing 7 supporting the .end of the shaft 8 ofthescrew 1 The screw 1 is hollow and has no threads on the discharge end; but is there formed as a cylinder made of one or more curved perforated plates 9 fastened in place thereon. This threadless continuation or extension of the screw body forms with the enveloping outer perforated shell 2 a press chamber through which the pulp passes under controllable pressure after it has left the threads of the screw. Vithin the shell 2 adjacent the outlet 1 one or more knife-like obstructions are fastened to prevent the pulp from turning around with the perforated plates 9 on the screw body in the press chamber. In practice these parts 10 do not materially retard the forward motion of the pulp. I

Movable with the screw body near the outlet 4 are cutting blades 11 which break the mass of pulp passing through the press chamber into small particles, thereby allowing a free discharge of these particles at the outlet. These blades are mounted on the throttling or discharge plug 12, which can be moved towards or away from the outlet carrying the stationary obstructing means 10,

thereby changing the clearance between the parts 10 and 11. The plug can slide on the screw 1 by reason of the feather key 13 on the screw engaging a keyway in the plug 12; and

'; partakes of the rotation of the screw.- Forward and backward motion can be imparted to the plug 12 by means of the slip collar 14, rotatably mounted between flanges on the end of the plug 12, and movable by arms 15 and a. a lever 16 mounted on a spindle 17 in bearings 18. The parts 15 and 16 are rigid with each other, and the sleeves 18 are fastened to the rods 5. Weights 19 are carried on the levers 16. At 20 is a threaded rod which passes through a threaded bar 21, pivotally attached to the levers 16. The rod 20, to which a hand wheel 22 is affixed, rests in a cavity or bearing 23 on the bearing 7 With the rod 20 and wheel 22 one can set and lock the plug 12 at a desired distance from the outlet at.

I have shown herein one embodiment of my invention and havein connection therewith described certain operative details of construction, but I do not desire to be limited thereto. For example, it is not necessary that the threadless end of the screw with the perforated plates fastened thereon be in one piece with the screw, but it can as well be a separate section secured to the screw.

I claim:

1. In a screw press, having a casing and a rotary screw forming an annular outlet space at the outlet end of the casing and the screw having a threadless part extending well beyond said outlet end, the improvement consisting of a frame at the free end of the threadless part, provided with a bearing receiving the axis end of the threadless part,

a rod means extending from the casing, an annular plug feathered on the threadless part, to be rotated with the screw and to have independent movement axially of the threadless part toward and away from the outlet space, and operative leverage means slidable at their pivotal portion on the rods of the frame acting on the plug for normally urging movement of the plug toward the outlet space, including a substantially horizontally positioned weighted arm as the motivating agent, whereby the raising or lowering of said weighted armwill axially move said plug away from or toward said outlet.

2. In a screw press, the combination with a casing and a rotary screw having an annular outlet space at the outlet end of the easing and the screw having a threadless part extending beyond said outlet end, of a frame supported by the casing and carrying a bearing receiving the axial end of the threadless part, an annular plug rotatable with the screw and shiftable axially of the threadless part for controlling the discharge of material through the outlet space, operative means on the frame for normally urging movement of the plug toward the outlet space, including a substantially horizontally projecting weighted arm asthe motivating agent, and means for supporting the weighted arm at an elevation including a hand operated vertically positioned adjusting screw the lower end of which is loosely seated in a socket in the frame so that as the weighted arm is raised the screw will accompany it.

3. 'In combination with a screw press having a easing and a rotatable screw therein forming an annular outlet space at the outlet end of'the casing and the screw having a threadless part extending beyond said outlet end, an annular plug for the outlet space, feathered on the threadless part to rotate therewith and to move axially thereon to and fromthe outlet space for controlling the discharge of material therethrough, means for controlling the axial movement of said plug, comprising a bell crank device mounted for rocking movement with one arm connected by a slip collar to the plug and the other arm extending substantially horizontallyand weighted to normally swing the device in a direction to move the plug toward the outlet space, and adjustable means for supporting the weighted arm at an elevation.

4. In a screw press having a casing and a screw therein forming an annular outlet space at the outlet end of the casing, the screw having a threadless part extending beyond said outlet end, and an annular plug slidable axially on the threadless part for controlling the discharge of material through the outlet space'and feathered onto said threadless part, the improvement for axially reciprocating the plug comprising a slip collar on said plug, a rocking arm pivotally and slidably supported by said casing and in connection with'said collar, and means for sliding said rockin arm whereby to cause movement of the p ug to close or open the annular outlet space.

5. In a screw press having a casing with I an outlet end and a screw with a threadless part extending outwardly through the 0utlet end of the casing and forming an annular outlet space therewith, an annular plug mounted on the threadless part for axial movement thereon and away from the outlet space, the improvement consisting of rods extending from the casing, connected bell crank devices pivotally mounted on said rods and slidable thereon, said devices'having one arm weighted and substantially horizontal, while the other arm is in connection with a slip collar on said plug, a bearing in engage- V ment with said rods, a shaft in connection with sand welghted arms, and means for ralsing and lowering said weighted arms whereby axially to move said plug backward or forward. 7 V

In testimony that I claim the foregoing as my invention, I have signed my name hereto.

RICHARD T. LANG. 

